This invention relates in general to data communication, and more particularly to a system for detecting subscriber loops.
Communication systems support the provisioning of voice, video, multimedia, data, or other services and information to subscribers arranged in a bridged network environment. Subscriber loops may occur in the bridged network environment when there is more than one active path between two subscribers. Subscriber loops in a bridged network environment may lead to the duplication of communications in a communications system resulting in a saturation of the network. Prior attempts to control loops in a bridged network environment include implementing spanning tree protocols and/or source routing protocols. A problem with this technique is that neither protocol is adequately scaleable for certain bridge network applications.
In accordance with the present invention, the disadvantages and problems associated with prior communication systems have been substantially reduced or eliminated.
In accordance with one embodiment of the present invention, a network device comprises a first network interface coupled to a plurality of subscribers using a communication network having a plurality of virtual circuits, each subscriber associated with a physical address. The network device further comprises a memory coupled to the first network interface and operable to store a plurality of subscriber associations, each subscriber association specifying a physical address of a corresponding subscriber and one of the plurality of virtual circuits. The network device further comprises a processor coupled to the memory and a second network interface coupled to the processor. The first network interface receives a communication from a particular subscriber. The communication identifies a destination. The second network interface forwards the communication toward the destination if the processor determines that a particular subscriber association stored in the memory specifies the physical address of the particular subscriber and the virtual circuit used to receive the communication.
Another embodiment of the present invention is a method for controlling subscriber loops that includes receiving a communication from a particular one of a plurality of subscribers using a particular one of a plurality of virtual circuits associated with a communication network. The communication identifies a destination. The method continues by storing in a memory a plurality of subscriber associations, each subscriber association specifying a physical address associated with a corresponding subscriber and one of the plurality of virtual circuits. The method concludes by forwarding the communication toward the destination if a particular subscriber association specifies the physical address of the particular subscriber and/the virtual circuit used to receive the communication.
Technical advantages of the present invention include a system that detects subscriber loops among subscribers in virtual circuit bridge network applications based upon the physical addresses of the subscribers, the virtual circuits used by network devices to receive communications from the subscribers, and subscriber associations maintained by the network devices. A particular advantage is that the network devices may detect subscriber loops in the system when determining whether to forward communications received from the subscribers to other components of the system. In this respect, the subscriber loop detection operation creates negligible system impact and does not raise scaleability issues encountered by prior attempts to detect and control subscriber loops. Another advantage is that the network devices may detect subscriber loops among subscribers employing digital subscriber line technology to access a communication network.